Steam generator



April 16, 1935. .J. JOHNSON 3997 934 STEAM GENERATOR Filed July 10,1955 5 Sheets-Sheet 1 fj rwdfio JOHIVJOHNSON A 99 19, 1999. I J. JOHNSON 1,997,999

STEAM GENERATOR Filed July 10, 1953 5 Sheets-Sheet 2 JOHNJOHNSON Apzrifl 16, 2935. J. JQHNSON 3,997,934

STEAM GENERATOR Filed July 10, 1933 3 Sheets-Sheet 5 JOHA/JOH/VSONY Patented Apr. 16, 1935 x: 1

UNITED STATES PATENT OFFICE 1,997,934 STEAM GENERATOR John Johnson, Cheam, England Application July 10, 1933, Serial No. 679,787

@Claims. (01. 122-480) As is well recognized, certain services neccssi- The accompanying drawings illustrate an tate the use of diiierent qualities of steam, either equipment according to the invention, Fig. 1 beat different times'or concurrently, to meet which ing a sectional side elevation of the boiler. Fig. separate boilers are most commonly used. This 2 is a front View, the left hand half of which is so, for instance, on board ship where donkey corresponds to a section on the line 2-2 of Fig. 1 5

boilers usually operate auxiliaries such as deck and the right hand half to an elevation with machinery, galley services etc. leaving the main parts removed. Fig. 3 is a sectional plan view boilers for propulsion. Space is at all times a corresponding to Fig. Zand Fig. 4 is a sectional consideration and, coupled with weight, is espeplan view corresponding to part of-Fig. 1. Fig.

cially so on a ship. The object of the present in- 5 is a front view of the boiler with parts removed. 10 vention is to provide a steam generator having a As here shown, 6 represents the boiler shell, much greater range of usefulness than has hith- 2 its internal furnaces, 3, 4 and 5 the associated erto been devised and one which hasa very high nests of return smoke tubes, 5 the refractory linefficiency as well as other attributes making it 'ing of the external combustion chamber, 7 the particularly applicable for marine work. tubular portion of a'superheater arranged in the 15 To this end advantageously a boiler is emcombustion chamber at the entrance end of the ployed of the type wherein the gases from furnest 4 of smoke tubes and connecting the external naces passing through the back plate of a cylinsaturated steam header 8 to the external superdrical shell are, on their 'way to return smoke heated steamheader 9. H) are gilled desupertubes, received in a combustion chamber conheating pipes located in the boiler, II is an auxtaining tubes designed to assist water circulation iliary steam stop valve adapted to admit steam in the boiler, and a superheating system likewise to the desuperheater and I2 is a superheated situated in said combustion chamber, the invenmain steam stop valve. [3 are the water circution consisting in combining with the super-' lating tubes which are arranged at a distance heater a desuperheater and selective delivery from the rear wall 6 such that gases from the valve means therefor, allocating the superheatfurnaces 2 can follow the paths indicated by the ing system to some fraction of the whole return arrows in Fig. 1. This gas flow is assisted by smoke tube system, arranging the water circubaffies M secured to the back plate l5 of the boiler lating tubes which bound the combustion chamwhich baflics act to constrict the path somewhat ber so that some of the gases from the furnaces and increase the velocity of flow towards and 30 can travel between and past them first in one across the tubes I 3. The smoke box 16 is divided direction and then in the opposite direction, proby walls I1 into three compartments correspondviding the exit ends of the furnaces with bafiles ing to the tube nests 3, 4 and 5 and each is to assist the flow of gases past the water circulatadapted to be independently placed in communiing tubes and providing the exit ends of the recation with the uptake "3 by appropriate manipspective nests of tubes of the smoke tube system ulation of dampers [9. One wall l8 of this upwith dampers whereby the conditions of gas flow take is separated from the front plate 20 of the in relation to the superheating system can be boiler by an air space formed in part by an inwidely varied to suit requirements. Finally the sulating envelope 2| which surrounds the whole whole boiler is preferably enclosed in a casing of the remainder of the boiler except the side which constitutes an air jacket to conserve heat wallslfi) of the combustion chamber where acand increase the overall efficiency. cess doors 22 are provided. 23 represents the,

Such a boiler will be found to meet all the imhot gas inlet t an a h a t ShOWn) Which portant demands of modern practice. Thus, in delivers into the boiler air jacket at addition to the inherent advantage of the boiler The arrangement is such that assuming a supproper, which includes a water capacity large yet ply of steam primarily, for say, propulsion only not unduly large as is demanded with an internal is required, then valve I2 will be opened and valve combustion chamber, it is possible to economiit closed. The degree of superheat at this time cally supply saturated or lightly superheated can be variously adjusted. For example normally steam alone such as may be required for the under full load all three furnaces 2 will be in use operation of auxiliaries while a vessel is in port; and all three dampers l9 opened. If one or other to supply steam for main engine use alone with or both of the wing dampers H! be closed, more varying degrees of superheat; or to utilize steam gases may be caused to flow through the cenof these diiierent characters simultaneously for tral nest l of tubes and influence the superboth such purposes. heater 1, thereby increasing the degree of superheat. On the other hand if the central damper H! be closed or partially closed and the others or one of the others alone left open the effect of the superheater I can be reduced until it may be regarded as negligible. Thus in port for example, saturated steam may be supplied to auxiliaries through the valve l2 and other distributing valves.

If, while superheated steam is being used as supplied through valve I2, it should be desired to supply saturated steam to auxiliaries, this can be done by opening valve II also.

What I claim is:-

1. In a steam generating plant, a boiler of the Scotch type having a plurality of furnaces, corelated nests of smoke tubes and an external combustion chamber connecting the furnaces with the smoke tube nests and containing water circulating tubes disposed so that gases from the furnaces can travel past and between them in opposite directions, a superheater located within said combustion chamber above the furnaces opposite the smoke tube nest of one of the same in the path of combustion gas flow, means at the back ends of the several furnaces for directing the gases past and between the circulating tubes as aforesaid and past the superheater, and dampers at the front end of each of the smoke tube nests whereby the flow of gases in relation to the superheater can be controlled therethrough for varying the degree of superheating.

2. A steam generating plant, comprising in combination, a multi-furnace boiler having corelated nests of smoke tubes and an external combustion chamber connecting the furnaces with the smoke tube nests and conta i g Water circulating tubes disposed so that gases from the several furnaces can travel past and between them in opposite directions, a superheater located within said combustion chamber above one of the furnaces opposite the smoke tube nest thereof in a position to be contacted by the combustion gases, and a damper at the front end of the nests of tubes arranged to vary the proportion of the gases passed through the various nests of smoke tubes whereby the proportion of the gases passed over the superheater may be varied.

3. A steam generating plant, comprising in combination with a multi-furnace boiler having corresponding nests of smoke tubes and a combustion chamber connecting the furnaces with the smoke tube'nests and containing water circulating tubes disposed so as to permit the gases from the furnaces to travel past and between them in different directions, a superheater located within said combustion chamber above one of the furnaces opposite the nest of smoke tubes therefor in a position to be contacted by the flowing combustion gases, and a damper at the front end of one of the nests of smoke tubes arranged to vary the proportion of the gases passed through the various nests of smoke tubes whereby the proportion of the gases passed against the superheater may be varied.

4. A steam generating plant, comprising a boiler having a central and two wing furnaces, a nest of smoke tubes associated with each of said furnaces, an external combustion chamber connecting the furnaces with the smoke tubes, a superheater located within said combustion chamber in the path of the combustion gas flowage above the central furnace directly opposite the nest of smoke tubes associated therewith, and a damper at the front end of the several smoke tube nests; said damper being arranged to vary the proportion of the gases passed through the various nests of smoke tubes whereby the proportion of the gases passed in contact with the superheater may be varied.

JOHN JOHNSON. 

